High performance VCSEL arrays for optical interconnection

High performance GaAs- and InGaAs-based selectively oxidized vertical-cavity surface-emitting laser (VCSEL) arrays emitting in the 780 to 980 nm wavelength regime are investigated as light sources for high bit rate optical interconnects. Solid source molecular beam epitaxy (MBE) with carbon as p-type dopant is used for crystal growth. Single-mode devices show record-high output powers up to 4.8 mW with a butt-coupling efficiency of more than 80% into single-mode fiber. Linear 1×8 and 1×16 as well as two-dimensional 4×8 VCSEL arrays have been employed as transmitters in optical fiber links. Non-return-to-zero (NRZ) pseudo-random bit sequence (PRBS) signals with 2³¹-1 wordlength at total data rates up to 24 Gb/s (8×3 Gb/s) have been transmitted over 500 m of multimode fiber. Bias-free data transmission of 2.5 Gb/s over 500 m of multimode fiber is demonstrated. Polymer optical fiber (POF) was used for short distance data transmission. A visible, red emitting VCSEL (λ=780 nm) is employed to transmit 2.5 Gb/s over 1 m of small core diameter (120 μm) POF. For all data transmission experiments bit-error rates (BERs) of better than 10^-11 were observed for back-to-back testing as well as for fiber transmission